This dissertation consists of three chapters, all of them are self-contained works. The first chapter, "Globalizing labor and the world economy: the role of human capital" is a joint work with Prof. Frédéric Docquier and Dr. Joel Machado. We develop a microfounded model of the world economy aiming to compare short- and long-run effects of migration restrictions on the world distribution of income. We find that a complete removal of migration barriers would increase the world average level of GDP by 13% in the short run and by about 54% after one century. These results are very robust to our idenfication strategy and technological assumptions. The second chapter, titled "Infrastructure Policy: the role of informality and brain drain" analyses the effectiveness of infrastructure policy in developing countries. I show that at low level of development, the possibility to work informally has a detrimental impact on infrastructure accumulation. I find that increasing the tax rate or enlarging the tax base can reduce the macroeconomic performance, while inducing long-run gains. These effects are amplified when brain drain is endogenous. The last chapter, titled "The role of fees in foreing education: evidence from Italy and the UK" is mainly empirical. Relying upon a discrete choice model, together with Prof Michel Beine and Prof Lionel Ragot I assess the determinants of international students mobility exploiting, for the first time in the literature, data at the university level. We focus on student inflows to Italy and the UK, countries on which tuition fees varies across universities. We obtain evidence for a clear and negative impact of tuition fees on international students inflows and confirm the positive impact of quality of education. The estimations find also support for an important role of additional destination-specific variables such as host capacity, expected return of education and cost of living in the vicinity of the university.